Transfusion of blood is a high-risk procedure. A patient may be killed or seriously harmed if the wrong type of blood or blood product is transfused, may be infected by blood bourn pathogens or may have unexpected reactions to blood products. For these reasons, considerable care is taken in the collection, processing, packaging, labeling and transport of blood units. Blood collection and supply agencies (Canadian Blood Services (Canada), American Red Cross, America's Blood Centers (USA), National Blood Services (UK)) keep detailed records of donations, processing, packaging and transport of blood products so that any single blood product can be traced back to an individual donor. Using this information, it should be possible to find and inform all patients who may have been exposed to blood from a particular donor that they might be at risk should a problem arise.
Blood transfusions are usually performed at hospitals. Hospital blood banks receive blood from the blood supply agency, perform any tests they may require to assure the type and quality of the blood and place the blood into the blood bank stock.
The first step in the transfusion process is testing of the patient's blood. This requires that a blood sample be drawn from the patient, correctly labeled with the patient's identification, and sent to the blood laboratory. The laboratory tests the patient's blood to determine the correct blood type for the patient, and any special requirements the patient may have. Once these factors are known, a suitable blood unit is retrieved from the blood bank stock and is labeled as suitable for the particular patient. The designated blood unit is placed into a storage location until it is needed. The blood laboratory keeps detailed records of the testing of the blood unit and the patient's blood.
When the patient requires blood for transfusion, someone is sent to the blood bank to collect the prepared blood unit. They are expected to ensure that they have collected the correct blood unit, and to record the time that the blood unit was retrieved. Accepted practice requires that blood that has remained outside of refrigeration for more than 30 minutes should not be transfused. It is the responsibility of the person collecting the blood from the blood bank to ensure that it is promptly delivered.
The transfusion step is tightly controlled. The caregiver administering the blood is required to follow a strict procedure that includes careful checking to ensure that the blood is labeled for the patient to be transfused, that the label is on the right blood unit, and that the unit is the correct blood type, meets any special requirements for the patient and has not expired. All of these checks are recorded to ensure that a full audit trail exists for the transfusion event, and to confirm that the correct checks were performed. This audit trail is the only means to link the original blood donation to the patient.
During the transfusion process, the caregiver is expected to record the patient's vital signs on a regular basis, and to record any reactions to the blood that the patient might experience. Reporting such reactions to the blood bank, and possibly on to the blood collection agency, may be appropriate to ensure that other patients are not similarly affected.
These procedures are fraught with latent errors. The original blood sample for matching the blood may be collected from the wrong patient, or may be mislabeled. The person picking up the blood unit from the blood bank may pick up the wrong blood unit. It may take too long to carry the blood unit to the patient, so that the blood has exceeded 30 minutes outside of refrigeration. There are even more risks during the transfusion process. The patient may not be wearing a suitable wristband providing positive patient identification, making it impossible for the caregiver to confirm that the blood unit is intended for that patient. The caregiver may misread the blood unit's unique identification number (which can be more 15 characters in length) when comparing it to the compatibility label. Errors may be made in transcribing the patient information or blood unit number into the patient record.
Despite the best efforts of blood supply agencies, it is not uncommon for the trail of a blood unit to be lost as soon as it is delivered to a hospital blood bank. There may be records within the blood bank showing which patient a blood unit was prepared and tested for, but once again, the blood bank usually loses track of the blood unit once it leave the blood bank. Most blood banks assume that any blood units not returned to the blood bank have been transfused. Blood supply agencies assume that any blood delivered to a hospital blood bank was either transfused or wasted.
There are products that attempt to ensure that blood samples drawn from a patient for testing are correctly labeled. (e.g. Safe Track, DataLog International Ltd., www.dataloguk.com, BDID, Becton Dickinson Ltd, www.bd.com, McKesson Corporation, www.mckesson.com) These systems do a good job of making sure that the label applied to the blood sample collected from the patient match the information on the patient's wristband, but do not offer any improvement in the completion of the audit trail for the complete transfusion process.
There have also been attempts to improve the monitoring of the movement of blood units from place to place, to ensure that the blood is correctly stored, that all movements are recorded and that the blood does is not outside of refrigeration for more than the allowed time. (e.g. Blood Track, DataLog International Ltd., www.dataloguk.com). These systems provide valuable audit information for movements from one storage location to another, but lose track of the blood unit in the critical last step, when the blood unit is removed for transfusion. In addition, the systems rely on users to scan various barcodes in the correct order to ensure that the movement of the blood units is correctly recorded.
There have also been attempts to improve the transfusion process itself. There are products that use barcode scanners to compare bar-coded information on the patient's wristband, the compatibility label and the blood unit to ensure a correct match. (e.g. Safe Track, DataLog International Ltd, www.dataloguk.com, Itrac, Immucor, www.immucor.com). These products do provide a means for improving the safety of the transfusion step, but do not return information to the blood bank to confirm the completion of the transfusion or report reactions. They also fail to provide a means to ensure that the blood unit to be transfused has been stored and transported correctly and within the acceptable time limits.